1. Field of the Invention
This invention relates generally to an apparatus and method for treating particulate material supplied in a bulk state by way of combining therewith a minor amount of liquid in a manner to achieve a uniform dispersion thereof throughout the material. More particularly, the invention relates to apparatus and method for enhancing the quality and appeal of a particulate food product and is shown here in an embodiment adapted for aromatizing a soluble coffee product with highly volatile aromas in a liquid carrier such as coffee oil, which aromatizing is accomplished in conjunction with the packaging of said coffee product for sale to the consumer.
In the manufacture of coffee products, especially soluble coffee, it has become a well established practice, particularly with respect to the higher quality products, to reintroduce into the product certain of the aromatics, at least the more desirable ones, which were necessarily lost or stripped from the product during one or more of the processing steps performed thereon. Achieving a successful reintroduction of the desired aromatics and retention thereof in the packaged product has met with problems and difficulties largely arising from the highly volatile nature of the desired aromatics sought to be so captured.
It has been a general practice in the aromatizing art to condense at low temperatures the aromatics recovered from the various processing operations and then add the condensate to a suitable carrier, such as coffee oil or the like, to provide an aroma enriched carrier which is then applied to the product, preferably just prior to packaging of the product.
In adding an aroma enriched carrier to particulate material such as soluble coffee whether it be in a powdery state, agglomerated, or flaked, it is of course important that the liquid carrier be dispersed evenly and uniformly throughout the mass of discrete particles so that not only each package of the product will contain the same amount of aroma enrichment but also that the carrier be dispersed uniformly throughout the product mass within each package. This is particularly true with a food product where the aromatization thereof is a significant factor in, the appeal of the product to the consumer thereby rendering it necessary that each portion of the product consumed or removed from a package be aroma-enriched to the same degree. It is also desirable that the aromatization of the product be performed within the shortest possible time lapse before sealing of the product in appropriate containers in order to minimize aroma loss by reason of its highly volatile nature.
Various methods have been employed for plating particulate materials such as soluble coffee with an aroma enriched carrier, and these methods have involved spraying techniques with respect to particulate material being fed on a conveyor belt or dropped in a falling stream or curtain. However, spraying of the enriched carrier regardless of the manner in which the product is fed with respect thereto, presents problems in start-up and stopping operations, adjustments of the spray nozzles, clogging thereof and more importantly with substantial loss of the aromatics due to the atomization of the carrier which tends to strip the aroma therefrom. Other techniques have been to inject the enriched liquid carrier into the product within its container and before the container is sealed. This technique while minimizing the loss of the aromatics to atmosphere through volatization thereof, fails to achieve a uniform dispersion of the aroma enriched carrier throughout the mass of particulate material so contained. The instant invention is concerned with a technique and apparatus improving upon the techniques such as above mentioned for aromatizing a particulate material with a highly volatile aromatic.
2. Description of the Prior Art
A typical apparatus for aromatizing soluble coffee utilizing a spray technology is disclosed in U.S. Pat. No. 3,148,070 issued Sept. 8, 1964 to A. R. Mishkin et al. In the disclosure of this patent soluble coffee in powdered form is supplied to the hopper of a filler in a falling circular stream which surrounds a spray nozzle connected to a supply of an aroma-enriched liquid carrier. The disclosure shows two forms of the apparatus; one where the aromatization is carried out under atmospheric conditions and other wherein it is carried out in an inert atmosphere. In both forms of the apparatus, atomization of the liquid carrier is called for with consequent loss of the highly volatile aromatic as a result thereof, as heretofore mentioned. The disclosure also teaches the use of separate nozzles connected to separate sources for a liquid carrier and a condensed aromatic for plating the product first with the carrier and then with the aromatic in successive steps.
In U.S. Pat. No. 2,825,190 issued Mar. 4, 1958 to R. F. Heald, apparatus is disclosed for aromatizing a particulate material, in this case soap beads, after being deposited in a container to be sealed. While this minimizes the time in which the material is exposed to atmosphere before being sealed in a container, it employs atomization of the liquid carrier wih the heretofore mentioned disadvantages incident thereto and furthermore precludes uniform dispersion of the carrier since the spraying is carried on within an immobile mass of particulate matter.
To Timoty A. Lubsen, et al. U.S. Pat. No. 3,769,032, issued Oct. 30, 1973 also discloses a method for aromatizing a particular material, in this case soluble coffee, after being packed in a container. In this disclosure the liquid carrier is injected into the packed mass in a drop wise or stream-like manner through a syringe or the like which is reciprocated in and out of the mass with the injection being timed to occur while the syringe is being withdrawn from the packed mass of particulate matter. This technique obviously is incapable of achieving uniform dispersion of the relatively minor amounts of carrier liquid throughout the entire mass of packed particulate material.